Improvement in coffer-dams



J. E. WALSH.

Coffer Dam.

(hailed ,gtatre @atrntdtiljirr.

Letters Patent No. 111,157, d ted January 24, 1871.

IMPRQVEMENT'IN coFFER-n Ms.

The Schedule referred to in these Letters Patent and makingpart of the same.

I, J OHN E. \VALSH, of the city, county, and State of New York, have made certain Improvements in Golfer-Dams, of which the following is a specification.

The object of this invention is tofurnish a better and more secure coffer-dam, in which piers or other structures are built under ,and below the surface of water, that can be easily moved and sunk in its place, and be as easily removed when desired, and that shall be water-tight; and

It consists in the construction of some of the parts of the shell that form the cofi'er-dam and in the structure as a whole.

In the drawing- Figure 1 represents a top view'of the cofi'er dam;

Figure 2, an'upright longitudinal sectional view of the inside; and i Figure 3, an upright longitudinal sectional view of the outside of the same.

A represents the walls of the coder-dam, constructed from metal plates a, of any convenient size and shape, which are joined together by riveting the plates ,to upright braces b.

Braces b are strengthened in a lateral direction by having a flange, 12, project centrally of its width a sufiicient distance to givethc required strength to resist the external pressure.

' The side walls are curved so that the transverse diameter is considerably greater in the center of the length of the side walls than at their extreme ends. This curvature is retained in the side walls by means of the, screw or hook-rods c c that extend longitudinally the entire length of the side walls, and are made 'fastat their ends to inwardly-projecting .lngs c' c,.which are secured in the side walls near their shoulders or extreme ends,'and by such curva- V tnre the side walls willresist a much greater external on the side walls, and on the other the inward curvature of the doors Between the angle-irons d and the side walls A on 7 one side, and the doors on the'oth'er, is interposed rubber-packing d".

'In'order to strengthen the doors B, bent metal plates 0 are bolted fast to their inner sides, as seen in fig. 1 at o, and extending inwardly at an angle from a direct line until they nearly meet when the doors are closed; they are then bent to conform to a line drawn from between the extreme outer ends of the doors at one end to that of the other, and-go parallel with each other to a short distance of the'out' ends of said doors, where they terminate, but are not made fast at their outer ends to the sides ot the curved doors.

At the outer or abutting edge of the doors rubber packing d is interposed, which packing is equal, or

about equal, in thickness to the two plates 0 at their.

onter'ends.

Near the outer edges of the doors is. a sufficient number of screw-bolt holes 0 to hold them in firm contact, when desired, by meansof the screw-bolts f and nuts f that pass through the door-plates and rubber packing, compressing the packing to a joint that will exclude the water, and also compress the loose outer ends of bent plates 0 together the whole length of their parallel sides, and form, by this means, a kind of flexible supporting braces to the doors.

For the convenience of lowering the cofl'er-dam, or the one-half of it, intd the position it is to occupy in building a pier or excavating the foundation of a pier, orlfor any other purpose where a cofi'er-dam would be used, suspending'rings D are inserted through the metal walls and braces, into which the suspending devices can be attached or hooked, and the structure raised'or lowered, as the case may be. v \Vhen the Golfer-dam is lowered into its proper place it is necessary to secure it in such position and guard against its being moved out of such place by strong currents in the water, orby other causes.

This is accomplished by firmly bolting or otherwise securing T-shaped braces h upon-the side walls, which may be made of metal or other sufliciently strong and proper material, and having a sliding pile, H, longer than. the height: of the side walls, with a groove in' one of its sides that will fit over the T-brace and freely slide vertically thereon, which is driven down into the ground below the bottom of the cofi'er-dam,

and securely holding it in place. By constructing the coffer-dam in the form herein described and shown, the pressure of the water upon its walls has the tendency and does act to compress the parts together'and keep the joints close, thus materially strengthening the structure as a whole when in and surrounded by water, consequently a coifer-dam 'can be constructed of thinner plates, have less weight, and costing less in the aggregate than if having parallel sides'on right lines.

I am aware that metal has been used in the con struction of coder-dams, and I lay no claim to its use. I am also aware that doors or gates and their joints packed with a flexible substance are in use. and I'do 'not broadly claimthcse; but 1 Having thus described my invention, What I do claim, and desire to secure by Letters Patent,is-

1. The bent plates 0, bolted at one end only to the inwardly-curved doors B,.in the manner and for the purpose shown.

2. The angle-iron d and packing d", in combination with the inwardly-curved hinged doors B, having flexible bent plates 0, interposed packing d", bolts f, and

nuts f, all constructed and arranged to operate in the manner described.

- 3. The cofier-dam herein described, composed of the outwardly-curved side walls A, strengthened by rods 0, inwardly-curved hinged doors B, having the flexible bent metal plates 0, packing d and d, and angleirons d, all the parts constructed and arranged to-. gether in the manner and for the purpose shown.

. JOHN E. WALSH. Witnesses:

WILLIAM A. How, GEO. A. BLACK. 

